Methanol Upcycling Toward Glycolaldehyde Synthesis Enabled by New High-Performance Photoredox Route.

Abstract

Glycolaldehyde (GA) possesses great potential to serve as the feedstock for the C2-based chemical industry and plays a vital role in the fabrication of pharmaceuticals and various chemicals. However, conventional GA synthesis methods suffer from harsh reaction conditions, low selectivity, and high purification costs. Herein, we for the first time demonstrate a new photoredox-catalyzed high-performance route toward dehydrogenative C─C coupling of methanol into GA paired with H2 generation over Ni-decorated ZnIn2S4, presenting an essentially untapped photocatalytic tactic for selective GA synthesis. Specifically, GA is formed with the production rate of 30.0 mmol·g-1·h-1 and the selectivity of 94% and the optimal apparent quantum yield at λ = 360 nm reaches 22%, the highest value reported to date for selective photocatalytic methanol conversion to GA. Mechanistic studies reveal that the decoration of Ni facilitates interfacial charge separation and transfer and promotes the formation of key radical intermediates of •CH2OH and •OCH3 for GA production. This work offers a conceptually new photocatalytic approach for the efficient and sustainable production of GA and enriches the content of methanol upcycling chemistry.